the 205 can take gl5 or motor oil, which royal purple product is better? I was going to go with 75-90w because Im moving to Fairbanks soon, and Royal purple is real pricey, i only want to do it once and am slowly going synthetic as I can afford it.

 

New Venture aka NP (New Process) recomends ATF in temps that you will see in Fairbanks. GL5 - 75/90 is going to be very thick at the extreme low temps you will see up there. Wednesdays high temp was -3 the low -9 - regular heat wave for this time of year.

Bob

 

Thanks Bob. Isn't the designation 75 meant for extreme low temps? Whats a guy supposed to run in the d60 and 70 then? My old dodge I had up there, an 87 w150, lived 2 alaska winters with very old, warm weather gear oil. It didn't like to move much at 50 below. I like my current truck much more than old belladona.

 

GL5 80W90 has the same viscosity as 20W50 motor oil. I don't know the exact specs on 75W90 but it would probably be similar to a 15W50 as far as viscosity. Here are the recomendations from a 2003 Check Chart Quick Lubrication Guide:

NP205....API Above 32 degrees 50wt, below 32 degrees 30wt
GL5 Above 90 degrees - 140W, above -10 degrees - 90W, below -10 degrees 80W

NP241....AF2 (Dexron), AP3 (Chrysler 7176E) this has been superceded by AP4 (Type 9602)

Hope this helps

Bob

 

I like the Amsoil 75w-90 MTL or Castrol Syntorq for the NP205. They are synthetic GL4/MT1 spec'd gear lubes that maintain pretty low pour points and still provide excellent high temp performance. Perfect all-around lubes for the transfer case.

 

I would go with the 75W-90.

 

75w90 works pretty good up here. I've run it in mine for years. It does get a bit thick at -40* but what dosen't. 75w90 for the diff(s) as well if you haven't already. That 90/140wt stuff turns to concrete in the cold.